Pivotal mounting for use in instruments of precision



Patented Dec, 13, 1927.

UNITED STATES PATENT OFFICE.

FREDERICK C. HoLTz, or SPRINGFIELD, ILLINOIS, ASSIGNCR- To sANGAMo ELECTRIC COMPANY, 0E SPRINGFIELD, ILLINOIS, A CORPORATION 0E ILLINOIS.

PIVCTAL MOUNTING ECR USE IN INSTRUMENTS 0E PRECISION.

Application led May 3, 1923. Serial No. 636,401.

My invention relates to the mounting of the rotating parts of delicate instruments, such as electricity meters and other like instruments of precision, in which it is extremely important that aberration or error due to friction be eliminated as completely as possible. Such instruments, and particularly electricity meters. are quite generally installed on moving objects, such as railway cars, automobiles, &c, ,where they are more or less subject to sudden shocks, and in shipment particularly, Where the meters are not maintained in their normal upright position,

they are often subjected to quite severe shocks, with the result that there is danger of the delicate bearings beingdistorted sufticiently to take a permanent set which would interfere withl the proper operation of the instrument, making it inaccurate. The object of my present inv ention is to provide an improved mounting which, under normal conditions, will maintain the parts in their proper operative position with the ivots in proper alinement, but which will iiave sufficient flexibility and elasticity to permit temporary yielding under abnormal strains or sudden shocks without permanent distortion of the pivots, and to restore the parts to perfect alinement when the strains are removed. This object I accomplish as illustrated in the drawing and hereinafter described. What I regard as new is set forth in the claims.

In the accompanying drawings in which I have shown my improvements applied to the moving parts of an ampere hour meter,

Fig. 1 is a side elevation, partly in section, of such parts of an ampere hour meter as are necessary to a clear understanding of my invention; and

Fig. 2 is a partial vertical sectional View showing a different form of bearing for the upper end of the armature shaft.

Referring to the drawings,-3 indicates a box or housing of insulating material, such as bakelite, comprising discs 4, 5 adapted to be securely connected together by screws 6, the opposing faces of said discs being countersunk to form a circular mercury chamber 7 in which the usual armature is arranged to rotate, as hereinafter described. The upper y disc 4 is provided with an upwardly projecting axially-disposed boss 8 having a passage 9 which communicates with the mercury chamber 7, and upon said boss is mounted a cylindrical member 10 ou which is secured a bracket 11 which supports the upper bearing of the armature shaft hereinafter referred to, and also other parts of the meter. The member 410 is also preferably provided with means for preventing spilling` of the mercury, such for example as that shown in Letters Patent to Otis White No. 1,413,817, dated Apri125, 1922.

Disposed .in the mercury chamber 7 is an armature 12 in the form of a dise mounted upon the lower end of an upright shaft 13 by means of a hub 14 of suitable non-magnetic material. Preferably, the lower end of the shaft 13 is tapered as shown in Fig. 1,

and it is secured to the hub 14 by a driving` fit. Said hub is of such diameter that it may rotate freely in the passage 9 into which 1t projects when the armature 12 is in its normal position, at which time it is immersed in and sustained by a bath of mercury contained in the chamber 7. The armature disc 12 is centered by means of a pivot pin 15 of very small diameter, the upper end of which projects through the bore of a ring jewel 16 fitted into a recess in the lower end of the hub 14 so that its bore coincides with the axis of the armature shaft 13. Preferably. the jewel 16 is held in place by burnishing or upsetting the lower margin of the hub 14 around the jewel so that it slightly overlaps the lower edge thereof, as shown in Fig. 1. As the armature 12 is secured to the hub 14 so as to rotate therewith, obviously the jewel 16 will also rotate with the armature about the pivot pin 15 as an axis. The lower end of the pivot pin 15 is driven into a socket in a plug 17 provided with a hollow stem 18 externally screw-threaded as shown in Fig. 1. This plug, which is made of suitable non-magnetic material, is screwed into a fixed block 19 embedded in a boss 20 projecting downwardly from the center of the lower member 5 of the housing 3; consequently said plug may readily be removed when necessary. The lower end of the plug 17 is preferably provided with a cap sleeve 21 which forms a limit stop determining the extent to which the plug may be screwed into the block 19. The lower margin of the sleeve 21 is upset over the lower end of the paratively short pivot pin were used. When 4without permanently distorting the plug 17, as shown at 22 in Fig. l, to secure these parts together. rlhe upper end of the stem 18 of the plug 17 carries an annular steel disc 23 which is fxedly secured in position so that its bore is coaxial with the borel of the jewel 16 and with the axis of the armature shaft 13 and pivot pin 15, and the length of the stem 18 is such that said disc 23 is located about midway between the point of attachment of the pivot pin 15 to the plug 17 and the point of engagement between said pivot pin and the jewel 16. By this arrangement the disc 23 forms an intermediate fulcrum support for normally holding the upper end portion of the pivot pin 15- against lateral movement, so that except when the upper end of said pivot pin is subjected to abnormal lateral strains the effect is substantially the same as though a com- A. 7 however, the upper end of the pivot pin is subjected to excessive strains that part of said pin below the disc 23 is capable of being deflected in response to deflection of the upper end thereof, thereby permitting its upper end to move laterally to a considerably greater extent without taking a permanent set, so that when the strain is removed the pivot pin returns to its normal coaxial position. As the armature disc 12 may move laterally far enough to engage the housing pivot pin 15, owing to the capability of the latter of being deflected without injury as above described, it will be apparent that the construction described insures the proper return of the parts to their normal position when any distorting strain is removed. As shown in Fig. 1, the hub 14 is provided with a transverse passage 24 immediately above the jewel 16 and communicating therewith, for the purpose of allowing the free circulation of mercury around the bearing, and to facilitate cleaning thereof when the parts are disassembled. By mounting the jewel on the armature, since the pivot pin 15 -does not rotate, there will be no tendency for accumulated dross orparticles to move along the pivot until they nally reach the jewel 16,

in which case they would be liable to cause' error in the registration of the meter. The position of the ring jewel 16 is such that it is at all times kept away from surfaces which might throw o considerable amount of impurities and cause error in the registration of the meter due to oxidation of such particles and accumulations around the rotating parts.

The upper end of the armature shaft 13 is centered and pivotally sup orted by an inverted cup jewel 25 mountedp in a tubular housing 26, at the lower marginal portion of which is an internally-projecting annular Fig. 1. The u per endof this pivot is rounded and po ished so that it bears properly in the recess of the cup jewel 25, but is capable of slight lateral movement up to the point where the cylindrical surface of said pivot comes in Contact with the inner face of the flange 27. As shown in Fig. 1, the upper end'of the armature shaft 13 extends through and fits tightly in, a sleeve 29 which carries the usual worm' 30 by which the usual meter train is driven, and the pivot 28 is secured in position by fitting it tightly in the upper end of said sleeve 29, a collar 31 on said pivot serving to limit the extent to which the base 32 of said pivot may enter said sleeve. y

llhe housing 26 in which the jewel 25 is mounted is itself fitted securely in the lower end of asleeve 33 which in turn is fitted in the bore of a shell 35 of suitable non-magnetic material which is screwed into a suitable socket in the upper end of the bracket 11 coaxial with the armature shaft 13. Within the upper end of the sleeve 33 and bearing against the head 36 of the shell 35 is a spring 37 which exerts downward pressure on the jewel 25 so as to hold it yieldingly in engagepivot 28 in contact with the jewel 25 is at all times prevented from disengaging the same by means of the yielding mounting of the jewel, and under conditions of' severe side vibration the cylindrical surface of said pivot comes in contact with the annular fiange 27 and prevents any possible scratching of the polished pivot. Under vibration, or due to any sudden motion of the moving system in a vertial direction, the excessive pressure of the ivot 28 against the surface of the jewel 25 orces the sleeve 33 in a vertical direction until the upper surface-of the armature 12'comes in contact with the upper half of the armature case, which, of course, preventsfurther movement in that direction. Immediately upon the removal of the impelling force, such as bythe placing of the meter in a vertical position, the jewel 25 and the pivot 28 resume their normal relation to 1 lim all possible conditions 'of severe vibration and shock the movingsystem is entirely protected, and that immediately upon installing the meter in a proper vertical position under the conditions normally met with in service, the moving system will immediately resume its proper position and rotate with maxi-- mum freedom.

In some cases where it is not. considered. necessary lo provide the mounting for the upper end of the armature shaft bearingsv illustrated in Fig. l, the mounting for the lower end of said shaft and the armature may be employed in connection with a pivot bearing of the usual type at the upper end ot' the armature shaft, as illustrated in .Fig f2, in which the pivot 28 is fitted in a ring jewel 38 that is provided with/an end bearing 39, which may be in the form of a cup jewel as shown in said figure. By this arrangement lateral movementof the upper end of the armature shaft is not permitted, and, therefore, the recess in the jewel 39 may be flattened instead of being spherical, as shown in Fig. 1.

lVhile my improvements are designed primarily for use in meter construction, they may be applied to various other kinds-of instruments, and the claims hereinafter made are, therefore, to be construed accordingly.

lhat I claim as my invention and desire to secure by Letters Patent, is

l. A pivotal mounting of the character described, comprising a flexible pivot pin non-rotatably securedy at one end in a suitable support alined With the pivotal axis of the mounting, the opposite end thereof being adapted to be deflected laterally, a member pivotally supported by the latter end portion ot' said pivot pin, and an intermediate fulcrum support for said pivot pin.

2. A pivotal mounting of the character described, comprising a flexible pivot pin nonrotatably secured at one end in a suitable support, said end of the pin being alined with the pivotal axis of the mounting, the opposite. end thereof being adapted to be deflected laterally, a member pivotally supported bythe latter end portion of said pivot pin, and a fixed member engaging and supporting said pivot pin at an intermediate point against lateral deflection.

3. A pivotal mounting of the character described. comprising a flexible pivot pin non-rotatably secured at one end in a suitable support, the opposite end thereof being adapted to be deflected laterally, a member pivotally supported by the latter end portion of said pivot pin, and an annular disc through which said pivot pin extends, said disc being fixedly supported approximately midway of the length of said pivot pin and forming an intermediate fulcrum support therefor relative to which the end portions of said pin can be flexed laterally.

4. A pivotal mounting of the character described, comprising a plug having a hollow stem, a flexible in having its inner end fixedly secured to said plug, its opposite end portion extending through and beyond said stem, and a fulcrum support carried. by said stem for the intermediate portion of said pin.

5. A pivotal mounting of the character described, comprising a plug adapted to be removably secured in a suit: lle support and having an externally screW-tlnfeaded hollow stem, a flexible pivotl pin one end portion of which extends into said hollow stem and is fixedly secured tosaid plug, its opposite end portion extending out beyond said stem'and being free to be deflected laterally, and an annular disc secured in said stem and forming an intermediate fulcrum support for said pivot pin.

(5. A pivotal mounting .for electricity meters comprising a flexible pivot pin nonrotatably secured at one end in a suitable. support, the opposite end thereof being adapted to be defiected laterally, a rotaryl armature pivotally engaged by the latter end portion of said pivot pin, and an intermediate fulcrum sup ort for said pivot pin, said pin having su cient length on each side of said fulcrum support to permit relative fiexure of the end portions thereof.

7. A pivotal mounting for electricity meters comprising a flexible pivot pin all portions of Which normally lie in a straight line, said pin being non-rotatably secured at one end in a suitable support, the opposite end thereof being adapted to be deflected laterally, a rotary armature pivotally engaged by the latter end portion of said pivot pin, and a fixed member engaging and supporting said pivot pin at an intermediate point against lateral deflection.

8. A pivotal mount-ing for electricity meters comprising a fiexible pivot pin nonrotatably secured at one end in a suitable support, the opposite vend thereof being adapted to be defiected laterally, a rotary armature pivotally engaged by the latter end portion of said pivot pin, and an annular disc through which said pivot pin extends, said disc being fixedly supported approximately midway of the length of said pivot pin and forming an intermedia-te fulcrum support therefor, whereby the portions of the pin on opposite sides of said disk will be flexed laterally in opposite directions when the aforesaid opposite end of the pin is deflected laterally.

9. A pivotal mounting for electricity meters comprising a plug having a hollow stem, a flexible pin having its inner end fixedly secured to said plug, its opposite end portion extending through and beyond said stem, a rotary armature pivotally engaged by the latter end portion of said pin, and a lll() lli) fulcrum support carried by said stem for the intermediate portion of' said pin, said pin flexing relative to said fulcrum support to permit lateral swinging movement of `said armature relative to a separate pivotal mounting.

10. An electricity meter, comprising a.

case enclosing a mercury chamber, an armature mounted to. rotate in said mercury chamber, an armature shaft connected with said armaturel and extending up through said case, means pivotally supporting the upper end of said armature shaft, and a flexible pivot pin engaging and centering said armature at the bottom thereof.

11. An electricity meter, comprising a case enclosing a mercury chamber, an armalture mounted to rotate in said mercury chamber, an armature shaft connected with said armature and extending up through said case, means pivotally supporting .the upper end of said armature shaft, a ring jewel coaxially mounted in said armature adjacent the bottom thereof, and a flexible pivot pin fitting in said ring j e\vel.

12. An electricity meter, comprising a case enclosing a mercury chamber. an armature mounted to rotate in said mercury chamber,

an armature shaft connected with said armature and extending up through Said case, means pivotally supporting the upper end of said armature shaft, a flexible pivot pin fixedly supported at its lower end in alinement with the axis of the armature, the upper end of said pivot pin being arranged to engage and center said armature, and an 1npivot pin relative to which the opposite end portions of said pin can be flexed laterally in opposite directions.

14. An electricity meter, comprising a 4case enclosing a mercury chamber and an axially disposed upwardly-extending passage communicating therewith, an armature adapted to rotate in said chamber and having a hub extending into said passage, a ring jewel coaxially mounted in said armature, a transverse passage in said hub communicating with the opening in said jewel, and a pivot pin supported at its lower end and extendmg into the opening in said jewel.

15. An electricity meter comprising a case enclosing a mercury chamber, an armature adapted to rotate in said chamber, an armature shaft connected with said armature and movable longitudinally, a pivot at the upper end of said shaft, an inverted cu jewel bearing upon theA upper end of said) pivot, and means movable longitudinally of the armature shaft for `supporting said cup ewe I 16. An' electricity meter comprising a case enclosing a mercury chamber, an armature adapted to rotate in said chamber, an armature shaft connected with said armature and movablelongitudinally, a pivot at the up per end of said shaft, an inverted cup jewel bearing upon the upper end of said pivot, meansl movable longitudinally of the armature shaft for supporting said cup jewel, and a spring for holding said cup jewelin engagement with said pivot.

17. An electricity meter comprising a case enclosing a mercury chamber, an armature adapted to rotate in said chamber, an armature shaft connected with said armature and movable longitudinally, a pivot at the upper end of said shaft, an inverted cup jewel bearing upon the upper end of said pivot, means movable longitudinally of the armature shaft for supporting said cup jewel, a spring for holding said cup jewel in engagement with said pivot, and an internally-projecting annular flange disposed around said pivot below said jewel, the internal diameter of said lflange being somewhat greater than that of the pivot, to permit limited lateral movement thereof.

18. A pivotal mounting of the character described, comprising a stationary member and a rotating member, a flexible pivot pin all portions of which normally lie in a straight line coincident with the axis of said rotating member, one end of said pin being secured to one of said members, the other end of said pin having pivotal engagement with the other of said members, and an intermediate fulcrum support for said pin relative to which the opposite end portions of said pin can flex laterally to permit lateral swinging movement of said rotating member about a center removed from said pivotal mounting. l

19. A pivotal mounting for electricity meters comprising a rotating armature member and a stationary supporting member, a fiexible pivot pin all portions of which normally lie in a straight line coincident with the axis of said armature member, one end of said pin being secured to one of said members, the other end of said pin having pivotal engagement with -the other of said mem` bers, and an intermediate fulcrum support for said pin relative to which the opposite end portions of said pin are free to flex laterally in opposite directions to permit lateral swinging movement of said rotating lili' member about a center remote from said fulcrum support.

20. In an electricity meter, the combination of an armature comprising a rotating disk and a supporting shaft therefor, a thrust bearing cooperating with said shaft and situated relatively remote from said disk, and laterally flexible pivot means for said armature situated in relatively close proximity to said disk for absorbing abnormal side motion of said disk.

21. In an electric meter, the combination of an armature comprising a rotating disk and a supportin shaft therefor, a thrust bearing cooperating With said shaft and situated relatively remote from said disk, laterally flexible pivot means for said armature situated in relatively close proximity to said disk for absorbing abnormal side motion of said disk, and means for positively 20 limiting the abnormal side motion of said disk to the permissible range of flexure of said lexible pivot means.

FREDERICK C. HOLTZ. 

